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| 6491232647 | where does development begin? | sperm and egg combine to form zygote | 0 | |
| 6491239251 | fertilization occurs when? | sperm fuses with egg to form zygote | 1 | |
| 6491245031 | why do millions of sperm ejaculate into female reproductive system? | -many are loss due to leakage from vaginal canal -acidic environment -sperm mobility -inability to pass cervical mucus -destruction by defense cells of uterus | 2 | |
| 6491256668 | embryo moves to uterus where it implants into ___________ | uterine wall. endometrial lining! | 3 | |
| 6491258525 | define: cleavage | mitotic division after fertilization, not much growth but smaller cells | 4 | |
| 6491269297 | cleavage can be either holoblastic or meroblastic. What do each mean? | holoblastic: total= human meroblastic: partial= reptiles | 5 | |
| 6491277863 | cleavage leads to ? | morula. embryo rapidly divides without increasing overall size | 6 | |
| 6491282342 | zygote --> ___________---> cleavage --> morula --> ___________. | zygote fertilization cleavage morula blastocysts | 7 | |
| 6491282343 | blastocyst | embryo accumulates fluid inside -zona pellucida starts to degenerate | 8 | |
| 6491373567 | cleavage--> morula--> blastocysts-->fluid-filled cavity -->single layer called___________ is formed. | trophoblast | 9 | |
| 6491378891 | egg cell is always asymmetric: animal pole: vegetal pole | animal: future ectoderm and mesoderm vegetable: future endoderm | 10 | |
| 6491388508 | zona pellucida in mammals | first envelope of egg, made of glycoproteins | 11 | |
| 6491393447 | fertilized egg is called the ? | zygote! | 12 | |
| 6491398840 | AFTER 4 cell divisions occurs--> leads to 16 cells called the? | morula | 13 | |
| 6491404872 | gastrulation | -formation of 3 basic germ layers -cells originally outside move inwards to become mesoderm | 14 | |
| 6491406447 | what are the 3 basic germ layers? | ectoderm, mesoderm and endoderm (neural tissue = ectoderm) | 15 | |
| 6491414210 | gastrulation begins with appearance of __________, 3rd week, which establishes? | primitive streak long axis of embryo | 16 | |
| 6491489975 | how is primitive streak formed? | epiblast cells thickens to form the primitive streak with primitive knot | 17 | |
| 6491504930 | epiblast cells invaginate from streak to form ____________ layer and replace hypoblast with _________ | mesoderm endoderm | 18 | |
| 6491508668 | hypoblast is a tissue type that forms ________________ | inner cell mass | 19 | |
| 6491511073 | no hypoblast = ? | multiple primitive streak in chicken embryos | 20 | |
| 6491578405 | what does tissue turn into before and after gastrulation? pregastrulation: gastrulation: | pregastrulation: tissue will turn into EPIDERMIS (skin) gastrulation: tissue will turn into NEURAL tissue (brain, spinal cord, eyes) | 21 | |
| 6491591774 | frog embryo- most of yolk is at one end of egg. cleavage occurs more rapidly at the ___________ end. yolk-free end: yolky end is: | yolk-free end yolk-free: animal pole yolky end: vegetal pole | 22 | |
| 6491616981 | birds and mammals: gastrulation begins with invagination in center of embryo, defining midline called the _______ _________ | primitive streak! **beginning of 3rd week | 23 | |
| 6491623721 | nervous system begins to develop at _________ stage in embryogenesis | late | 24 | |
| 6491627908 | prior to nervous system formation, these 3 main cell layers must be generated | endoderm, mesoderm, and ectoderm | 25 | |
| 6491631052 | endoderm | innermost layer -gives rise to gut, lungs, pancreas, liver | 26 | |
| 6491632849 | mesoderm | middle layer -gives rise to connective tissue, heart, muscle, bone, vascular system | 27 | |
| 6491635231 | ectoderm | outermost layer -gives rise to major tissues of central and peripheral NS system | 28 | |
| 6491640027 | entire NERVOUS system arises from what tissue? | ECTODERM!! | 29 | |
| 6491687783 | What is the purpose of neural plate? | become neural tissue | 30 | |
| 6500764965 | when neural plate folds inward into a cylinder it is called a _____ ______. some cells at edge of neural plate become migratory _________ ________ | neural tube neural crest | 31 | |
| 6500810325 | neurulation is formation of (2) | neural plate and neural tube | 32 | |
| 6500820025 | caudal region of neural tube gives rise to __________ rostral region of neural tube gives rise to __________ | caudal: spinal cord rostral: brain | 33 | |
| 6500825207 | what is definition of neural induction? | development of neural tissue | 34 | |
| 6500828731 | what triggers neural induction? | 1. inducing factors 2. molecules | 35 | |
| 6500834821 | complex programming: inducing factor the _______________ that a cell occupies early in development is critical for determining its ________. | -signaling molecules from other cells -freely diffusible, can act over long range or local -the POSITION that a cell occupies early in development is critical for determining its FATE. | 36 | |
| 6500836060 | complex programming: molecules | -are surface receptors that mediate effect of inducing factors -activation of receptors MODULATE TF activity -REGULATE gene expression that encode specialized functions of cell | 37 | |
| 6500867265 | competence of a cell is? | ability of a cell to respond to inductive signals | 38 | |
| 6500869797 | competence of a cell depends on (3) | - enough receptors -transduction molecules - TF expressed by cells | 39 | |
| 6500875131 | A cell's fate is determined by (3) | - signals it is expose to -location in the embryo -profile of genes it expresses as a consequence of developmental history | 40 | |
| 6500883447 | Neural plate is induced by signals from the adjacent ____________ layer | mesoderm | 41 | |
| 6500886756 | role of mesoderm was conducted by scientists Spemann and Mangold. what did they do? | - took dorsal lip of blastopore from pigmented and translated onto an embryo of albino frog. - results: separate primitive streak and new neural tube formed at site of transplant and new body axis was mostly made up of non-pigmented cells. | 42 | |
| 6500898990 | Spemann organizer | dorsal lip is a neural inducer and "organizer" of entire body axis | 43 | |
| 6500907260 | How was Noggin, a neural inducer, identified? | - frog embryos were irradiated with UV light (neural tissue does not form) -cDNA from organizer were injected into UV treated embryo -Noggin! | 44 | |
| 6500920094 | how is mesoderm formed? | both animal and vegetal poles must interact to form mesoderm | 45 | |
| 6500929854 | is noggin a neural inducer and mesoderm inducer? | no! only neural genes are turned when animal cap+ noggin --> neural tissue noggin+mesoderm inducer --> neural tissue + mesoderm | 46 | |
| 6500940163 | what is Chordin? | -direct neural inducer -another gene expressed only in organizer - injection of chordin induces another body axis and rescues centralized embryos | 47 | |
| 6500951309 | what is follistatin? | -involved in mesoderm induction -binds and INHIBITS activin -promotes neural induction | 48 | |
| 6500973461 | three molecules secreted from organizers are ? these 3 molecules promote ? | noggin, follistatin and chordin promote NEURAL induction! | 49 | |
| 6500982740 | capacity of ectodermal cells to undergo neural differentiation is suppressed by signals transmitted by neighboring cells, mediator of these suppressive signals is called? | bone morphogenetic protein (BMP) | 50 | |
| 6605569571 | chrodin and noggin are both __________ and __________ for neural development | sufficient and necessary | 51 | |
| 6501004790 | BMP signaling is found to ________ differentiation of ectoderm to epidermis and _____________ neural differentiation | promote suppress | 52 | |
| 6564539858 | knockout of proneural genes: overexpression of proneural genes: | -/-: no neuron development +/+: ectopic neuron and sense organs | 53 | |
| 6564542667 | neuroblast is a ________ cell that will develop into a _________ occurring after ________ phase | neuroblast is a DIVIDING cells that will develop into a NEURON occurring after MIGRATION phase | 54 | |
| 6564543985 | how do neuroblast commit to neuronal fate? | neuroblast differentiate and thus commit to neuronal fate | 55 | |
| 6564545607 | difference between neuroblast and neuron | neuroblast can still divide! (undergo mitosis) neuron cannot = post mitotic | 56 | |
| 6564555640 | Achaete scute genes code for transcription factors in ? these bind to short stretches of DNA called? | basic-helix-loop helix (bHLH) family E-boxes | 57 | |
| 6564564661 | restricting Achaete scute to one cell causes? | lateral inhibition, in which neighbors suppress each other so that not all cells are forming neurons | 58 | |
| 6605578991 | what is lateral inhibition | neighboring cells suppress each other so that not all cells are forming neurons | 59 | |
| 6564569040 | how does lateral inhibition occur? | Delta and receptor Notch and Asc expression | 60 | |
| 6564571753 | Asc promotes ______ expression. Low levels of _______ promote neuroblast fate, while _______ levels promote epidermal fate. when ______ binds to _______, intracellular part of _______ gets cleaved. Cleaved ______ goes into nucleus to repress Asc transcription | Asc promotes DELTA expression. Low levels of NOTCH promote neuroblast fate, while HIGH levels promote epidermal fate. When DELTA binds to NOTCH, intracellular part of NOTCH gets cleaved. cleaved NOTCH goes into nucleus to repress Asc transcription | 61 | |
| 6564575124 | two neighbors expressing both Asc, Delta, and Notch equally will? | repress each other equally. *remember low notch levels = neuronal fate | 62 | |
| 6564579836 | if one neighboring cells produces _______ Asc proteins, it will cause neighboring cell to stop expressing _________ and _______. | MORE Asc and Delta genes = neighboring cell thus becomes epidermal fate | 63 | |
| 6564582624 | over time, expression of Asc is restricted to ___ cell, this cell will have ? | 1 cell this cell will have strongest initial expression | 64 | |
| 6564585873 | what are the 3 primary layers of embryo? | ectoderm: outer layer becomes the nervous system (CNS/PNS and skin) mesoderm: middle layer, becomes muscles, skeleton endoderm: innermost layer, becomes lining of viscera | 65 |
